Some pathologies of the gastrointestinal (GI) tract, involve epithelial damage, erosions, and ulcers. For example, inflammation of the GI tract mucosa (typically in the stomach), such as gastritis, can be characterized, inter alia, based on the endoscopic appearance of the gastric mucosa (e.g., varioliform gastritis). Other pathologies may involve irregularities or abnormal appearances of folds, polyps or color indications (such as bleeding) on the GI tract wall. Detection of these pathologies at an initial stage plays an important role in enhancing the probability of a cure.
Screening populations for initial signs of GI tract pathologies is typically carried out by non-invasive methods including x-ray images in which a patient intakes x-ray opaque (radio-opaque) material (barium, gastrographine, or others). The material resides for some time on the walls of the GI tract, enabling examination of the x-ray images of the GI-tract. This technique has several drawbacks, namely, low detection rate and exposure to x-ray radiation. Other screening methods include viewing the GI tract walls or lumens by means of appropriate endoscopes. For example, flexible upper endoscopy is often performed to evaluate for a gastrointestinal etiology of pain such as mucosal inflammation (esophagitis, gastritis, duodenitis), ulceration, or a neoplasm. Risks associated with flexible upper endoscopy include injury to the bowel wall, bleeding, and aspiration. Upper endoscopy is usually performed under conscious sedation, which carries risks as well. Furthermore, patients typically need to take a day off of normal activities due to the lasting effects of conscious sedation. Finally, the endoscopy procedure is clearly a cause of discomfort, pain and vomiting in many patients. Even the physical dimensions of the endoscope can be a cause for fear. Such risks, along with the prospect of incapacitation and fear, are often used as justifications by patients for delaying or altogether avoiding gastroscopic diagnosis.
Visualization of the GI tract, including the more difficult to reach areas, such as the small intestine, is possible today using an ingestible imaging capsule. Images of the GI tract are obtained by a miniature image sensor carried by the capsule and are transmitted to an external recorder to be later viewed on a workstation. Sensing other parameters of the GI tract, such as pH or temperature, are also possible by using ingestible transmitting capsules. Ingestible capsules may be moved through the GI tract by the natural movement of peristalsis. However, in larger or voluminous lumens, such as the stomach or large intestine, the view or sensing capacity of a capsule may not cover the entire surface of the lumen wall.